Six charities will benefit from “American Idol‘s” annual “Idol Gives Back” show April 9: the Children’s Defense Fund, The Global Fund, Make It Right, Malaria No More, Save the Children and the Children’s Health Fund.

Bridget Marquardt

NBC’s “The Biggest Loser,” meanwhile, is making some history with a rule change: For the first time, viewers, and not the show’s contestants, will determine who competes in the “Final 3” for the show’s $250,000 purse. Voting begins after the April 8 episode, with the results unveiled during the live finale (April 15). Tonight’s show (8 p.m./Ch. 4) is the makeover episode featuring Bravo’s Tim Gunn.

Last, but not least:

* NBC Universal has sold “House” and “Monk” into syndication next fall. “House” (Hugh Laurie) will air on Ch. 5, “Monk” (Tony Shalhoub) on Ch. 4.